Box Canyon Dam is a concrete gravity dam on the Upper Sacramento River impounding Lake Siskiyou reservoir, in Siskiyou County, northern California.

The dam and reservoir are located in Box Canyon of the eastern Trinity Mountains and within the Shasta–Trinity National Forest, southwest of the town of Mount Shasta and Mount Shasta peak.

Box Canyon Dam is 1,100 feet (340 m) long and 209 feet (64 m) high. The dam is owned and operated by Siskiyou County's Flood Control & Water Conservation District and Siskiyou Power Authority, and was completed in 1965 to provide flood control. In 1965, a powerhouse was installed to provide hydroelectric power.

Beginning in April 1959, the State of California appropriated funding to study the feasibility of building the dam.

The Box Canyon Trail begins on the north side of Box Canyon Dam, following the Upper Sacramento River down the narrow canyon to the outskirts of the town of Mount Shasta. The Lake Siskiyou Trail encircles the lake, including a crossing atop the dam.

• Dams on the Sacramento River
• List of dams and reservoirs in California

• Living Shasta Photography Blog: Lake Siskiyou's Box Canyon Dam — photo gallery, interiors/exteriors of dam + powerhouse.
• "Virtualguidebooks.com: 360 degree view of Box Canyon Dam".